Japanese Encephalitis in Indonesia

Japanese encephalitis occurs in rural agricultural areas throughout Asia and is transmitted by bites from the culex mosquito. These mosquitoes breed where there is abundant water, such as in rice paddies, and feed primarily on birds and domestic animals, usually pigs. The culex mosquitoes are night feeders, so there is less chance of Japanese encephalitis transmission during the day.

Japanese encephalitis vaccination is no longer available in Indonesia, so travelers who require the vaccine should get it prior to traveling there.

Although encephalitis means inflammation of the brain, most Japanese encephalitis infections cause no symptoms. If symptoms do develop, they include nausea, vomiting, headache and fever. A severe attack may cause coma and has a mortality of up to 25 perecent. Of those who survive severe infections, about 30 percent have permanent brain damage.

To prevent Japanese encephalitis, sleep in well-screened accommodation and avoid sleeping outdoors near large concentrations of animals. Prevent mosquito bites and consider vaccination when risk is significant.

Prevelance in Indonesia

Travelers visiting resort areas have a low risk of contracting the disease. Affected areas include Kalimantan, Bali, Nusa, Tenggara, Sulawesi, Mollucas, Papua and Lombok. Transmission probably occurs year-round, and peak risk times are associated with increased rainfall and rice cultivation. Peak periods include November through March, June, and July in some years. Human cases have occurred in Bali, Java and possibly Lombok.